Classroom
noun
The teaching room is just a classroom.
きょうしつ
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
ここは、一年生の教室ですよ。
This is a classroom for first-graders.
代わりの先生が中々教室に来ません。
A substitute teacher still hasn't come to the classroom.
今日は、マフィンを作るための教室に行きます。
Today, I'm going to the class to make muffins.